Dosage of C is highly personal, varying widely among individuals and also according to state of health. Your average or normal dose is determined by finding your bowel tolerance for C and staying just within it.
Most people, especially those who dislike swallowing tablets, will find ascorbic acid (Vitamin C) as the fine crystals, dissolved in water or fruit juice, most convenient and least expensive for use at home. Away from home, 1 gram (1000 milligrams) tablets usually work out best. If bowel tolerance is 10 grams or fewer, 500 milligram (1/2 gram) tablets permit more finely divided doses. Generally, the more frequent the doses the better, within practical limits.
Take 5 grams – 1 rounded teaspoon (5000 milligrams) the first day, divided into as many doses as practical. If you have one loose bowel movement that day, decrease the dosage to a rate of 3-4 grams per day; and that is your average dose.
Arthritics in particular will benefit by taking about ¼ of their daily dose in the form of time release tablets at bedtime, to minimize or eliminate early morning aches and pains. Time release tablets are available, at slightly higher cost than regular tablets, in 1000 mgs. and in 1500 mgs. (1½ gram) sizes, the latter being most economical.
Busy, active people often find it most convenient to take all of their C in time release tablets, ¼ of the daily dose every 6 hours of so, or with meals and at bedtime.
Most people have no difficulty in this respect. Some, especially if taking regular tablets, have moderate stomach upset the first couple of days; this can be relieved with bicarbonate or Titralac chewable tablets (but not milk of magnesia, which is a laxative and can confuse the bowel tolerance picture).
Taking as much of the daily dose as possible (while keeping it finely divided) with food and the rest with substantial amounts of water will be enough to protect most sensitive stomachs. For some, the best remedy will be time release tablets, which are mostly past the stomach when they dissolve.
A very few may find that they can take C in quantity only in the non-acid form of sodium ascorbate or calcium ascorbate, available in crystals and in tablets. If on a salt restricted diet, avoid sodium ascorbate, even though experimental work shows that it does not affect high blood pressure.
Other than stomach upset, side effects are very rare and last only a few days (i.e., mild rash; wakefulness at night). They should be ignored and worked through. Otherwise, no amount of C is harmful in any way.
Caution: If you are a diabetic receiving insulin or an oral drug, see your doctor first. C potentiates insulin or insulin substitutes, i.e., increases their effectiveness so that the same results can be obtained with a smaller dose. Since over correction of diabetes can be as bad as under correction, your doctor will have to work with you to determine your new decreased medication. In addition, large doses of Vitamin C can interfere with certain blood and urine tests for glucose. The DIASTIX test for urine sugar and Chem Strip BG for blood sugar are not interfered with. Stool tests for evidence of bleeding may also be falsely positive.
There is a possibility that large doses of C over a prolonged period may induce deficiencies in certain vitamins and minerals. It is therefore, wise to take a good comprehensive vitamin and mineral supplement.
When your body is under any sort of stress (sickness, injury, allergy, etc.), your need for C may increase greatly, and your bowel tolerance will increase correspondingly. People who normally get a loose stool at, say, 10 to 15 grams a day, may when sick, tolerate )and, therefore need) 50 or even 100 or more grams a day without bowel symptoms.
When you feel a cold or the flu coming on, immediately take 5-8 grams all at once (carry C with you for this purpose). If, in an hour, you still feel symptoms, begin taking 3 grams an hour. If in another hour the symptoms have not almost entirely disappeared, increase the dose to 4 grams an hour; then, if necessary, to 5 or even 6. That single loose stool will tell you when it is time to taper off from these doses. It is necessary to hit a viral disease hard; taking, say, 40 grams a day won’t do much for a 70 gram or 80 gram cold or flu. If you take enough, you should be able to function normally and in relative comfort throughout the course of the disease, and without complications.
Those normally using time release tablet should keep at least 500 grams of regular (non time release) C on hand for illnesses, as crystals or tablets or both. “All at once” means immediately available from, which time release isn’t.
Allergic symptoms may also be relieved completely by increasing your dosage. So may mental or emotional stress. So may many other temporary afflictions. Bowel tolerance always tells you how much C your body wants and can use.
Modified from a sheet by William H. Burke, Kalamazoo, Michigan. Information based upon the article, Vitamin C Titrating to Bowel Tolerance by R. C. Cathcart, MD, Medical Hypothesis, 7:1359-1376, 1981.